The present invention pertains to improved methods of insert molding a film laminate, or the like, over a plastic substrate, or a portion thereof, and to fused film laminated parts made thereby.
A variety of injection molded parts have been made and used for automobile body and trim parts. For example, bumpers, body panels, doors, filler panels, wheel covers, dashboards, armrests and other parts have been made via injection molding techniques. Additionally, with regard to automobile exteriors, bodyside trim moldings, beltline moldings, roof moldings and window are made via injection molding of polyvinylchloride (PVC) or other thermoplastic materials.
In order to provide a painted surface for these parts, film lamination techniques are commonly employed. In accordance with these processes, a paint film laminate is insert molded with the desired thermoplastic to fuse the film laminate over the injection molded part. The resulting injection molded part is ready for assembly without subsequent painting.
The paint film laminate used in these insert molding techniques may comprise a backing sheet to which paint layers are adhered to form a colored side of the laminate. Typically, the backing sheet comprises an extruded thermoplastic sheet. In such paint film laminates, a paint film laminate, comprising a cast dried continuous paint coating, is provided over the backing sheet. The paint film laminate may consist of a monocoat, a clear coat over a base coat or a clear coat and a base coat with interposed print or design. The paint film laminate, including base coat, clear coat and print or design, if desired, may, for example, range from about 0.5-4 mil. in thickness.
The laminated paint films are typically provided in a roll, unwound, then trimmed to a proper “preform” size and shape, ready for insertion into the injection mold. The preform is usually placed along the cavity side of the mold with the painted side thereof facing the mold cavity surface.
In some instances, the pre-sized paint film laminate may be placed along the core side of the mold unshaped. The mold is then clamped and the desired molten resin is injected into the mold cavity. Heat and pressure conditions in the mold partially melt the backing sheet and a melt bonding or fusion of the injected resin and film laminate occur. Injection molds used for these processes are commonly rear or edge gated so that the molten resin is directed along the backside of the film laminate, pressing the show face side of the film laminate against the surface of the mold cavity. Techniques utilized to insert mold plastic parts covered by such paint film laminates are disclosed, for example, in U.S. Pat. Nos. 5,599,608; 5,783,287; 5,746,962 and 6,168,742 of common assignment herewith. The subject matter of these disclosures is incorporated by reference herein.
It has become increasingly popular to insert or co-mold bumper, rocker panel, side trim, and chin spoiler parts for autos and trucks which incorporate a paint film laminate which includes two different colored sections of the paint film in neighboring relation to each other on the surface of the part.
Conventionally employed insert molding techniques for manufacturing such plural colored laminate parts often result in an unsightly appearance wherein the transition line or border between neighboring colors of the paint film presents an uneven or wavy appearance that stands in contrast to the desired straight line or clean edge appearance that is intended between neighboring colors. This undesirable appearance may be caused, for example, by shrinkage or distortion of the paint film during the co-molding process.
Accordingly, there is a need in the art for a process for manufacturing a plural color paint film laminate structure and resulting structure wherein the transition area or boundary between neighboring colors on the show surface of the part appears straight or linear, providing a sharp, clean transition from one color area to its neighboring color area.